Ceramer composition incorporating fluoro/silane component and having abrasion and stain resistant characteristics

ABSTRACT

A curable ceramer composition, coated articles and methods for making and curing the composition. The curable ceramer comprises a fluoro/silane, a crosslinkable silane, a curable binder precursor, and a colloidal inorganic oxide. The ceramer has a long shelf life before cure and can be used to provide cured ceramer coatings and articles having stain resistance, abrasion resistance and hardness.

RELATED APPLICATION INFORMATION

This application is a division of prior application Ser. No. 09/389,252,filed Sep. 3, 1999, now U.S. Pat. No. 6,245,833 B1, which was acontinuation-in-part of prior application Ser. No. 09/209,117, filedDec. 10, 1998, now abandoned, which was a continuation-in-part of thenprior application Ser. No. 09/072,506, filed May 4, 1998, now abandoned.

FIELD OF THE INVENTION

This invention relates to abrasion resistant protective coatings andmethods of making the same. This invention also relates to abrasionresistant coatings derived from a ceramer composite.

BACKGROUND OF THE INVENTION

Thermoplastic and thermosetting polymers are used to form a wide varietyof structures for which optical clarity, i.e., good light transmittance,is a desired characteristic. Examples of such structures include cameralenses, eyeglass lenses, binocular lenses, retroreflective sheeting,non-retroreflective graphic displays, automobile windows, buildingwindows, train windows, boat windows, aircraft windows, vehicleheadlamps and taillights, display cases, eyeglasses, watercraft hulls,road pavement markings, overhead projectors, stereo cabinet doors,stereo covers, furniture, bus station plastic, television screens,computer screens, watch covers, instrument gauge covers, bakeware,optical and magneto-optical recording disks, and the like. Examples ofpolymer materials used to form these structures include thermosetting orthermoplastic polycarbonate, poly(meth)acrylate, polyurethane,polyester, polyamide, polyimide, phenoxy, phenolic resin, cellulosicresin, polystyrene, styrene copolymer, epoxy, and the like.

Many of these thermoplastic and thermosetting polymers have excellentrigidity, dimensional stability, transparency, and impact resistance,but unfortunately have poor abrasion resistance. Consequently,structures formed from these polymers are susceptible to scratches,abrasion, and similar damage.

To protect these structures from physical damage, a tough, abrasionresistant “hardcoat” layer may be coated onto the structure. Manypreviously known hardcoat layers incorporate a binder matrix formed fromradiation curable prepolymers such as (meth)acrylate functionalmonomers. Such hardcoat compositions have been described, for example,in Japanese patent publication JP02-260145, U.S. Pat. No. 5,541,049, andU.S. Pat. No. 5,176,943. One particularly excellent hardcoat compositionis described in WO 96/36669 A1. This publication describes a hardcoatformed from a “ceramer” used, in one application, to protect thesurfaces of retroreflective sheeting from abrasion. As defined in thispublication, a ceramer is a hybrid polymerizable composite (preferablytransparent) having inorganic oxide particles, e.g., silica, ofnanometer dimensions dispersed in an organic binder matrix.

Many ceramers are derived from aqueous sols of inorganic colloidsaccording to a process in which a radiation curable binder matrixprecursor (e.g., one or more different radiation curable monomers,oligomers, or polymers) and other optional ingredients (such as surfacetreatment agents that interact with the colloids of the sol,surfactants, antistatic agents, leveling agents, initiators,stabilizers, sensitizers, antioxidants, crosslinking agents, andcrosslinking catalysts) are blended into the aqueous sol. The resultantcomposition is then dried to remove substantially all of the water. Thedrying step may also be referred to as “stripping”. An organic solventmay then be added, if desired, in amounts effective to provide thecomposition with viscosity characteristics suitable for coating thecomposition onto the desired substrate. After coating, the compositioncan be dried to remove the solvent and then exposed to a suitable sourceof energy to cure the radiation curable binder matrix precursor.

SUMMARY OF THE INVENTION

The manufacture of ceramer compositions can be challenging due to theextremely sensitive characteristics of the colloids of the aqueous sol.Particularly, adding other ingredients, such as binder matrix precursorsor other additives, to such sols tends to destabilize the colloids,causing the colloids to flocculate, e. g., precipitate out of the sol.Flocculation is not conducive to forming high quality coatings. First,flocculation results in local accumulations of particles. Theseaccumulations are typically large enough to scatter light which resultsin a reduction of the optical clarity of the resultant coating. Inaddition, the accumulation of particles may cause nibs or other defectsin the resultant coatings. In short, flocculation of the colloids causesthe resultant ceramer composition to be cloudy, or hazy, and thus,coatings formed from the ceramer composition could be cloudy or hazy aswell. Conversely, if colloid flocculation were to be avoided, theresultant ceramer composition would remain optically clear, allowingcoatings containing the ceramer composition to be optically clear aswell.

Thus, the manufacture of ceramer compositions may require specialprocessing conditions that allow binder precursors or additives to beincorporated into a sol to avoid colloid flocculation. Unfortunately,the processing conditions developed to manufacture one ceramercomposition are often not applicable to the manufacture of a ceramercontaining different components.

One method of manufacturing ceramers from aqueous, colloidal solsinvolves incorporating one or more N,N-disubstituted (meth)acrylamidemonomers, preferably N,N-dimethyl (meth)acrylamide (hereinafter referredto as “DMA”), into the binder matrix precursor. The presence of such aradiation curable material advantageously stabilizes the colloids,reducing the sensitivity of the colloids to the presence of otheringredients that might be added to the sol. By stabilizing the colloids,the presence of materials like DMA makes ceramers easier to manufacture.In addition to enhancing colloid stability, DMA provides other benefits.For example, ceramer compositions containing DMA show better adhesion topolycarbonate or acrylic substrates and better processability ascompared to otherwise identical ceramer compositions lacking DMA.

Unfortunately, the use of DMA also has some drawbacks. A ceramercomposition incorporating DMA tends to attract or bind with acidiccontaminants (coffee, soda pop, citrus juices, and the like) in theenvironment. Thus, ceramers incorporating DMA tend to be more vulnerableto staining.

Accordingly, it would be desirable to find an alternative approach formaking ceramers without DMA, or with reduced amounts of DMA, such that(1) the colloids are sufficiently stable during ceramer manufacture, (2)the resultant ceramer is stain resistant, or (3) the resultant ceramerretains excellent hardness and abrasion resistance.

Fluorochemicals have low surface energy characteristics that wouldsatisfy at least one of the aforementioned criteria. Specifically,because compositions with lower surface energy generally tend to showbetter stain resistance, the incorporation of a fluorochemical into aceramer would be likely to enhance the ceramer's stain resistance.Unfortunately, however, the incorporation of fluorochemicals into aceramer sol is extremely difficult. For example, because fluorochemicalsare both hydrophobic (incompatible with water) and oleophobic(incompatible with nonaqueous organic substances), the incorporation ofa fluorochemical into a ceramer sol often results in phase separation,e.g., colloid flocculation. This undesirable colloid flocculation canalso result during the stripping process, when water is typicallyremoved from the blended aqueous sol.

Consequently, it would further be desirable to find a way to provideceramers with good stain resistance using fluorochemicals or other stainresistant additives, while avoiding compatibility and hardness problemsgenerally associated with fluorochemicals.

The present invention provides a method for effectively incorporating afluorochemical into a ceramer composition. According to the invention, anonionic fluorochemical containing both a fluorinated moiety and ahydrolyzable silane moiety (the “fluoro/silane component”) can besuccessfully incorporated into a ceramer sol, without causingappreciable colloid flocculation, to provide ceramer coatings withsurprisingly long shelf lives and excellent stain resistantcharacteristics. Ceramers incorporating such a fluorochemical alsoretain a high level of abrasion resistance and hardness.

The present invention involved not just discovering the advantagesoffered by the fluoro/silane component, but also involved developingprocessing techniques that would allow the fluoro/silane component to beincorporated into the sol without causing flocculation of the colloids.Flocculation can be substantially prevented if the fluoro/silanecomponent is added to an admixture containing a colloidal inorganicoxide and a curable binder precursor (the “first admixture”) in thepresence of a surface treatment agent containing both a hydrolyzablesilane moiety and a polymerizable moiety (a “crosslinkable silanecomponent”). The fluoro/silane component and the crosslinkable silanecomponent may be combined to form a second admixture, which is thencombined with the first admixture to form a third admixture which afterstripping will provide a curable ceramer composition of the presentinvention. Alternatively, the crosslinkable silane component may becombined with the first admixture individually, after which thefluoro/silane component may then be added. In contrast, if thefluoro/silane component is added to the sol individually in the absenceof, e. g., before, the crosslinkable silane component, colloidflocculation tends to occur as soon as the crosslinkable silanecomponent is added or during stripping. The effects caused by the orderof addition of the crosslinkable silane and the fluoro/silane tend to beobserved in larger scale processes rather than in bench scale processes.In bench scale processes, it may be possible to add the fluoro/silanecomponent to the sol in the absence of the crosslinkable silane withoutobserving appreciable flocculation.

The present invention also provides ceramer compositions containing amixture of inorganic oxides. The oxides are present as a major portionof one inorganic oxide and a minor portion of a different inorganicoxide, resulting in cured ceramer coatings with improved physicalproperties compared to coatings made with only one inorganic oxide.

Accordingly, in one aspect, the present invention relates to a method ofmaking a curable ceramer composition by combining a fluoro/silanecomponent with an admixture containing one or more colloidal inorganicoxides and a curable binder precursor. The fluoro/silane component isadded to the admixture in the presence of a crosslinkable silanecomponent. The fluoro/silane component contains a hydrolyzable silanemoiety and a fluorinated moiety. The crosslinkable silane componentcontains a hydrolyzable silane moiety and a polymerizable moiety otherthan a silane moiety. The curable binder precursor contains one or morepolymerizable moieties copolymerizable with the polymerizable moiety ofthe crosslinkable silane component. At least a portion of the colloidalinorganic oxide is surface treated by the fluoro/silane component. Theresultant ceramer composition may be used directly if desired. When thecolloids are provided as an aqueous sol, the ceramer composition istypically stripped and optionally diluted in an appropriate solvent toprovide a viscosity suitable for coating onto a desired substrate.

In another aspect, the present invention relates to a method of makingan abrasion resistant ceramer coating using free-radically-curableembodiments of the ceramer composition described above. At least aportion of a substrate surface is coated with the ceramer composition,after which the coated substrate is irradiated with an amount of curingenergy under conditions effective to at least partially cure the coatedfree-radically-curable ceramer composition, whereby an abrasionresistant ceramer coating is formed on the substrate.

In another aspect, the present invention relates to afree-radically-curable ceramer composition. The ceramer compositionincludes a free-radically-curable binder precursor; and a plurality ofsurface treated, colloidal inorganic oxide particles that are surfacetreated with the fluoro/silane component.

In another aspect, the present invention relates to a cured, abrasionresistant ceramer composite derived from this free-radically-curableceramer composition.

The ceramer composition of the present invention can be utilized toprovide substrates with durability, dry soil resistance, long-lastingstain release properties and in some cases, water and oil repellency.Thus, the present invention also relates to a composite structure,comprising a polymeric substrate having a coatable surface. A cured,abrasion resistant ceramer coating of the present invention is providedon the coatable surface of the substrate.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

The embodiments of the present invention described below are notintended to be exhaustive or to limit the invention to the precise formsdisclosed in the following detailed description. Rather the embodimentsare chosen and described so that others skilled in the art mayappreciate and understand the principles and practices of the presentinvention.

One embodiment of a preferred ceramer composition of the presentinvention is prepared from ingredients containing a compound having atleast one hydrolyzable silane moiety and at least one fluorinated moiety(“fluoro/silane component”), a compound having at least one hydrolyzablesilane moiety and at least one polymerizable moiety other than a silanemoiety (“crosslinkable silane component”), a curable binder precursorhaving at least one polymerizable moiety that is co-polymerizable withthe polymerizable moiety of the crosslinkable silane component, and oneor more colloidal inorganic oxides. Preferably, the fluoro/silanecomponent and the crosslinkable silane component are nonionic inembodiments of the invention in which the colloidal inorganic oxide isprovided as a sol. The use of nonionic materials minimizes the tendencyof the colloids to flocculate when the ingredients are combined.Preferably, the polymerizable moieties of the crosslinkable silanecomponent and the curable binder precursor are free-radically-curable.

A wide range of these materials may be incorporated into the ceramercomposition with beneficial results. Preferably, the compositionincludes from about 4 to about 20 parts by weight of the crosslinkablesilane component per 1 part by weight of the fluoro/silane component. Itis additionally preferred that the composition includes from about 10 toabout 80 parts by weight of the curable binder precursor per 100 partsby weight (including the weight of the dispersant or other liquidmedium) of the colloidal inorganic oxide. It is also preferred that thecomposition includes about 1 to about 20 parts by weight of thecrosslinkable silane and fluoro/silane components per 100 parts byweight of the colloidal inorganic oxide (again including the weight ofthe dispersant or other liquid medium). In embodiments of the inventionin which the colloids are provided as a sol, e.g., an aqueous sol, thesol preferably includes about 2 to about 50, preferably about 20 toabout 50 percent by weight of the colloids.

Expressed on a solids basis, the ceramer compositions of the inventionpreferably contain about 50 to about 60 weight percent curable binderprecursor and about 35 to about 40 weight percent colloidal inorganicoxide solids, with the balance (totaling about 5 to about 10 weightpercent) being crosslinkable silane and fluoro/silane.

Suitable fluoro/silane components include those having at least onehydrolyzable or hydrolyzed group and a fluorochemical group.Additionally, suitable fluoro/silane components can be polymers,oligomers, or monomers and typically contain one or more fluorochemicalmoieties that have a fluorinated carbon chain having from about 3 toabout 20 carbon atoms, more preferably from about 6 to about 14 carbonatoms. These fluorochemical moieties can contain straight chain,branched chain, or cyclic fluorinated alkylene groups or any combinationthereof. The fluorochemical moieties are preferably free ofpolymerizable olefinic unsaturation but can optionally contain catenary(in-chain) heteroatoms such as oxygen, divalent or hexavalent sulfur, ornitrogen. Perfluorinated groups are preferred, but hydrogen or halogenatoms can also be present as substituents, provided that no more thanone atom of either is present for every two carbon atoms.

A class of useful fluoro/silane components can be represented by thefollowing general formula:

(S_(y))_(r)—W—(R_(f))_(s)  (1)

In this formula, S_(y) represents a hydrolyzable silane moiety; R_(f)represents a fluorinated moiety; r is at least 1, preferably 1 to 4,more preferably 1; s is at least 1, preferably 1 to 4, more preferably1; and W is a linking group having a valency of r+s.

Preferably, each R_(f) moiety of Formula (1) independently is amonovalent or divalent, nonionic, perfluoro moiety that may be linear,branched, or cyclic. If R_(f) is divalent, both valent sites of such anR_(f) moiety preferably are linked to W directly as illustrated by thefollowing formula:

From Formula (2), it can be seen that each divalent R_(f) moiety bondsto two valent sites on W. Accordingly, s of Formula (1) is incrementedby 2 for each such divalent moiety.

Any of a wide variety of nonionic perfluoro moieties are suitable foruse as R_(f). Representative examples of suitable perfluoro moietiesinclude perfluoroalkyl, perfluoroalkylene, perfluoroalkoxy, oroxyperfluoroalkylene moieties having 1 to 20, preferably 3 to 20 carbonatoms. Perfluorinated aliphatic moieties are the most preferredperfluoro moieties.

Preferably, each S_(y) moiety of Formula (1) independently is amonovalent or divalent, nonionic hydrolyzable silane moiety that may belinear, branched, or cyclic. The term “hydrolyzable silane moiety”refers to a hydrolyzable moiety containing at least one Si atom bondedto at least one halogen atom or at least one oxygen atom in which theoxygen atom preferably is a constituent of an acyloxy group or an alkoxygroup. Thus, representative examples of preferred hydrolyzable silanemoieties suitable for use as S_(y) may be represented by the followingformulae:

Generally, R¹ and R² independently may be any nonionic, monovalentsubstituent other than hydrogen. Additionally, r¹ and R² may be linear,branched, or cyclic. In embodiments according to Formula (4), R¹ and R²may be co-members of a ring structure. Thus, representative examples ofmoieties suitable for use as R¹ and R² include any alkyl, aryl, alkaryl,acyl, alkenyl, arylene or heterocyclic moieties, combinations thereof,or the like. Any of such moieties, if cyclic, may include a plurality ofrings if desired. For example, aryl moieties may be aryl-arylstructures. In preferred embodiments, each of R¹ and R² is independentlyan alkyl group of 1 to 4 carbon atoms or an acyl group such as acetyl(CH₃CO—) or substituted or unsubstituted benzoyl (C₆H₅CO—). Mostpreferably each of R¹ and R² independently is a lower alkyl group of 1to 4 carbon atoms, more preferably CH₃—.

Z is preferably a halogen atom or —OR³. In embodiments in which —OR³ isan alkoxy group, R³ preferably is an alkyl group of 1 to 8, morepreferably 1 to 4, and most preferably 1 to 2 carbon atoms. Inembodiments in which —OR³ is an acyloxy group, R³ preferably has theformula —C(O)R⁴, wherein R⁴ generally may be any nonionic, monovalentmoiety other than hydrogen. Representative examples of moieties suitableas R⁴ include any alkyl, aryl, or alkaryl moieties, and combinationsthereof. Any of such R⁴ moieties, if cyclic, may include a plurality ofrings if desired. In preferred embodiments, R⁴ is CH₃—.

Generally, W of Formula (1) may be any nonionic moiety capable oflinking the at least one S_(y) moiety and the at least one R_(f) moietytogether. Preferably, W contains a backbone of 4 to 30 atoms and maycontain one or more moieties such as an alkylene moiety, an ethermoiety, an ester moiety, a urethane moiety, a carbonate moiety, an imidemoiety, an amide moiety, an aryl moiety, an alkaryl moiety, analkoxyaryl moiety, sulfonyl, nitrogen, oxygen, combinations of these,and the like.

A preferred class of compounds according to Formula (1) is representedby any of the formulae

wherein n is 1 to 20, preferably 3 to 20; R⁷ is a monovalent moiety,preferably an aryl, alkyl, or alkyaryl moiety, more preferably an alkylmoiety of 1 to 4 carbon atoms; X¹ is an alkylene group of 1 to 10 carbonatoms, and Z, R¹, R² and R³ are as defined above.

Representative specific examples of preferred compounds according toFormula (1) include the following compounds:

C₅F₁₁CH₂OCH₂CH₂CH₂Si(OCH₂CH₃)₃

C₇F₁₅CH₂OCH₂CH₂CH₂Si(OCH₂CH₃)₃

C₇F₁₅CH₂OCH₂CH₂CH₂SiCl₃

C₈F₁₇CH₂CH₂OCH₂CH₂CH₂SiCl₃

C₁₈F₃₇CH₂OCH₂CH₂CH₂CH₂SiCl₃

CF₃CF(CF₂Cl)CF₂CF₂SO₂N(CH₃)CH₂CH₂CH₂SiCl₃

C₈F₁₇SO₂N(CH₃)CH₂CH₂CH₂Si(OCH₃)₃

C₈F₁₇SO₂N(CH₃)CH₂CH₂CH₂Si(OCH₃)₃

C₈F₁₇SO₂N(CH₂CH₃)CH₂CH₂CH₂Si(OCH₃)_(av1.9)[(OCH₂CH₂)_(av6.1)OCH₃]_(av1.1)

C₇F₁₅CH₂O(CH₂)₃Si(OCH₂CH₂OCH₂CH₂OH)₃

C₇F₁₅CH₂CH₂Si(CH₃)Cl₂

C₈F₁₇CH₂CH₂SiCl₃

Cl₃SiCH₂CH₂CH₂OCH₂(OCF₂CF₂)₈CH₂OCH₂CH₂CH₂SiCl₃

CF₃O(CF₂CF(CF₃)O)₄CF₂C (═O)NHCH₂CH₂CH₂Si(OC₂H₅)₃

CF₃O(C₃F₆O)₄(CF₂O)₃CF₂CH₂OC (═O)NHCH₂CH₂CH₂Si(OCH₃)₃

Cl₃SiCH₂CH₂OCH₂(CF₂CF₂O)₈(CF₂O)₄CF₂CH₂CH₂CH₂SiCl₃

C₈F₁₇CONHC₆H₄Si(OCH₃)₃

 C₈F₁₇SO₂N(CH₂CH₃)CH₂CH₂CH₂Si(OCH₃)_(av1)(OCH₂CH₂(OCH₂CH₂)₂OCH₃)_(av2)

A particularly preferred embodiment of a fluoro/silane componentaccording to Formula (1), for example, is represented by the formula

The compound according to Formula (11) is commercially available fromMinnesota Mining and Manufacturing Company, St. Paul, Minn. under thetrade designation FC405. Methods of making such a compound andfluoro/silane compounds in general are described in U.S. Pat. No.3,787,467 to Lucking et al., the disclosure of which is hereinincorporated by reference.

Useful fluoro/silane components can be prepared, e.g., by reacting (a)at least one fluorochemical compound having at least one reactivefunctional group with (b) a functionalized silane having from one toabout three hydrolyzable groups and at least one alkyl, aryl, oralkoxyalkyl group that is substituted by at least one functional groupthat is capable of reacting with the functional group of thefluorochemical compound(s). Such methods are disclosed in U.S. Pat. No.5,274,159 (Pellerite et al.).

Crosslinkable silane components suitable for use in the ceramercomposition of the present invention are commercially available fromnumerous sources. Generally, suitable crosslinkable silane componentscontain at least one hydrolyzable silane moiety and at least onepolymerizable moiety other than a silane moiety. The polymerizablemoiety preferably contains either (meth)acrylate, allyl, styryl, amino,or epoxy functionalities, while the hydrolyzable silane group is usuallyan alkoxy silyl moiety (generally methoxy or ethoxy) which serves as abinding site to hydroxy-functional inorganic substrates via displacementof the alkoxy groups. Additional information concerning crosslinkablesilane components may be found in the book by E. P. Pleuddeman (“Silanecoupling Agents”, Plenum Press, N.Y., 1982, pp. 20-23 and 97) as well asin technical reports by S. Sterman and J. G. Marsden entitled “Theory ofMechanisms of Silane Coupling Agents in Glass Reinforced and FilledThermoplastic and Thermosetting Resin Systems”, Union CarbideCorporation, New York, and “A Guide to Dow Corning Silane CouplingAgents”, Dow Corning Corporation, 1985, pp. 2-13, the disclosures ofwhich are incorporated by reference herein.

Crosslinkable silane components suitable for use in the ceramercompositions of the present invention may be polymers, oligomers, ormonomers and may preferably be represented by the formula

(S_(y))_(q)—W^(o)—(R_(c))_(p)  (12)

In Formula (12), S_(y) represents a hydrolyzable silane moiety asdefined above with respect to Formulae (1) and (2); R_(c) is a moietycontaining curable functionality, preferably free-radically-curablefunctionality; q is at least 1, preferably 1 to 4, more preferably 1; pis at least 1, preferably 1 to 4, more preferably 1; and W^(o) is alinking group having a valency of q+p. Compounds according to Formula(12) and methods of making such compounds are described in U.S. Pat. No.5,314,980, the disclosure of which is incorporated by reference herein.

Generally, W^(o) of Formula (12) may be any nonionic moiety capable oflinking the at least one S_(y) moiety and the at least one R_(c) moietytogether. Preferably, W^(o) has a backbone of 4 to 30 atoms and maycontain one or more moieties such as an alkylene moiety, an ethermoiety, an ester moiety, a urethane moiety, a carbonate moiety, an imidemoiety, an amide moiety, an aryl moiety, an alkaryl moiety, analkoxyaryl moiety, arylsulfonyl moiety, nitrogen, oxygen, combinationsof these, and the like.

Embodiments of compounds according to Formula (12) in the form of silanefunctional (meth)acrylates include, for example, 3-(methacryloxy)propyltrimethoxysilane, 3-acryloxypropyl trimethoxysilane,3-(methacryloxy)propyltriethoxysilane,3-(methacryloxy)propylmethyldimethoxysilane,3-(acryloxypropyl)methyldimethoxysilane,3-(methacryloxy)propyldimethylethoxysilane,3-(methacryloxy)methyltriethoxysilane,3-(methacryloxy)methyltrimethoxysilane,3-(methacryloxy)propyldimethylethoxysilane, 3-methacryloxypropenyltrimethoxysilane, vinyldimethylethoxysilane, vinylmethyldiacetoxysilane,vinylmethyldiethoxysilane, vinyltriacetoxysilane, vinyltriethoxysilane,vinyltriisopropoxysilane, vinyltrimethoxysilane, vinyltriphenoxysilane,vinyltri-t-butoxysilane, vinyltris-isobutoxysilane,vinyltriisopropenoxysilane, vinyltris(2-methoxyethoxy)silane, andmixtures thereof. Of these, 3-(methacryloxy)propyl trimethoxysilane,3-acryloxypropyl trimethoxysilane,3-(methacryloxy)propylmethyldimethoxysilane and3-(methacryloxy)propyldimethylethoxysilane are preferred. Furthermore,embodiments of crosslinkable silane components according to Formula (18)in the form of silane functional polyolefins can be produced fromcommercially available starting materials by any of several methods.

Exemplary crosslinkable silane components are described in theabove-mentioned Pleuddeman reference and in U.S. Pat. Nos. 4,491,508 and4,455,205 to Olsen et al.; U.S. Pat. Nos. 4,478,876 and 4,486,504 toChung; and U.S. Pat. No. 5,258,225 to Katsamberis, all of which areincorporated herein by reference.

In the practice of the present invention, free-radically-curablefunctionality refers to functional groups directly or indirectly pendantfrom a monomer, oligomer, or polymer backbone (as the case may be) thatparticipate in crosslinking or polymerization reactions upon exposure toa suitable source of radiant (e.g., UV or thermal) curing energy. Suchfunctionality generally includes not only groups that crosslink via acationic mechanism upon radiation exposure but also groups thatcrosslink via a free radical mechanism. Representative examples ofradiation polymerizable moieties suitable in the practice of the presentinvention include epoxy groups, (meth)acrylate groups, olefiniccarbon-carbon double bonds, allylether groups, styrene groups,(meth)acrylamide groups, combinations of these, and the like.Representative examples of curing energy include electromagnetic energy(e.g., infrared energy, microwave energy, visible light, ultravioletlight, and the like), accelerated particles (e.g., electron beamenergy), or energy from electrical discharges (e.g., coronas, plasmas,glow discharge, or silent discharge).

The colloidal inorganic oxides for use in the present invention includeparticles, powders, and oxides in solution. The colloidal inorganicoxides are desirably substantially spherical in shape, and relativelyuniform in size (e. g., they have a substantially monodisperse sizedistribution or a polymodal distribution obtained by blending two ormore substantially monodisperse distributions). It is further preferredthat the colloidal inorganic oxides be and remain substantiallynon-aggregated (substantially discrete), as colloidal aggregation canresult in precipitation, gellation, or a dramatic increase in solviscosity and can reduce both adhesion to the substrate and opticalclarity. Finally, it is preferable that the colloidal inorganic oxidesbe characterized by an average particle diameter of about 1 nanometer toabout 200 nanometers, preferably from about 1 nanometer to about 100nanometers, more preferably from about 2 nanometers to about 75nanometers. These size ranges facilitate ease of dispersion of theparticles into coatable ceramer compositions and provide ceramercoatings that are smoothly surfaced and optically clear. Averageparticle size of the colloids can be measured using transmissionelectron microscopy to count the number of particles of a givendiameter.

A wide range of colloidal inorganic oxides can be used in the presentinvention. Representative examples include colloidal titania, colloidalalumina, colloidal zirconia, colloidal vanadia, colloidal chromia,colloidal iron oxide, colloidal antimony oxide, colloidal tin oxide, andmixtures thereof. The colloidal inorganic oxide can be a single oxidesuch as silica, a combination of oxides such as silica and aluminumoxide, or a core of an oxide of one type (or a core of a material otherthan a metal oxide) on which is deposited an oxide of another type.

In one preferred embodiment, for example, the inorganic oxide may be amixture containing a major amount of a first or primary inorganic oxide,e.g., silica, and a minor amount of a second or additive oxide,preferably an aluminum oxide such as a sodium aluminate. As used herein,“major amount” means that the inorganic oxide includes a sufficientamount of the primary oxide (preferably at least about 80% by weight,more preferably at least about 95% by weight, and most preferably atleast about 98% by weight) such that the composite properties of theresultant ceramer are primarily due to such primary oxide. “Minoramount” means that the inorganic oxides include a sufficient amount ofthe additive oxide to enhance at least one property of the resultantuncured or cured ceramer composition.

It has now been discovered that it is much easier homogeneously todisperse inorganic oxides in uncured ceramer compositions or within solsfrom which the ceramers are to be derived when the inorganic oxideincludes both a primary inorganic oxide and at least one additiveinorganic oxide. For example, cured ceramer coatings incorporatingsilica and aluminum oxide particles have shown better abrasionresistance and improved processability than otherwise identical ceramercoatings having no additive oxide.

The optimum amount of an additive oxide to be incorporated into aceramer composition will depend upon a number of factors including thetype(s) of additive oxide(s) being used, the desired end use of theceramer composition, and the like. Generally, if too little of anadditive oxide is used, little benefit will be observed. On the otherhand, if too much of an additive oxide is used, then the resultant curedceramer coating may be hazier than desired, and abrasion resistance maybe reduced. As one suggested guideline for preferred embodiments inwhich the corresponding cured ceramer coating is desired to be opticallyclear and abrasion resistant, the ceramer composition may include about100 parts by weight of silica and about 0.01 to about 10, preferablyabout 1 to about 2 parts by weight of an oxide other than silica,preferably an aluminum oxide.

The colloidal inorganic oxide is desirably provided in the form of a sol(e.g., a colloidal dispersion of inorganic oxide particles in liquidmedia), especially sols of amorphous silica. Unlike other forms in whichthe colloidal inorganic oxide particles may be supplied (e.g., fumedsilica which contains irregular aggregates of colloidal particles),colloids of such sols tend to be substantially monodisperse in size andshape and thus enable the preparation of ceramer compositions exhibitinggood optical clarity, smoothness, and surprisingly good adhesion tosubstrates. Preferred sols generally contain from about 2 to about 50weight percent, preferably from about 25 to about 45 weight percent, ofcolloidal inorganic oxide.

Sols useful in the practice of the present invention may be prepared bymethods well known in the art. For example, silica hydrosols containingfrom about 2 to about 50 percent by weight of silica in water aregenerally useful and can be prepared, e.g., by partially neutralizing anaqueous solution of an alkali metal silicate with base to a pH of about8 or about 9 (such that the resulting sodium content of the solution isless than about 1 percent by weight based on sodium oxide). Sols usefulin the practice of the present invention may also be prepared in avariety of forms, including hydrosols (where water serves as the liquidmedium), organosols (where organic liquids are used as the liquidmedium), and mixed sols (where the liquid medium contains both water andan organic liquid). See, e.g., the descriptions of the techniques andforms given in U.S. Pat. Nos. 2,801,185 (Iler) and 4,522,958 (Das etal.), whose descriptions are incorporated herein by reference, as wellas those given by R. K. Iler in The Chemistry of Silica, John Wiley &Sons, New York (1979).

Due to their low cost, and environmental considerations, silicahydrosols (also known as aqueous silica sols) are preferred for use inpreparing the ceramer compositions of the invention. The surfacechemistry of hydrosols makes them particularly well suited for use inthe ceramer compositions of the present invention. For example, whencolloidal inorganic oxide particles are dispersed in water, the sol isstabilized to some degree due to common electrical charges that developon the surface of each particle. The common electrical charges tend topromote dispersion rather than agglomeration or flocculation, becausethe similarly charged particles repel one another.

Hydrosols are commercially available in both acidic and basic forms andwith a variety of particle sizes and concentrations under suchtrademarks as “LUDOX” (E. I. DuPont de Nemours and Co., Inc. Wilmington,Del.), “NYACOL” (Nyacol Co., Ashland, Mass.), and “NALCO” (NalcoChemical Co., Oak Brook, III.). Additional examples of suitablecolloidal silicas are described in U.S. Pat. No. 5,126,394, incorporatedherein by reference. Although either acidic or basic sols are suitablefor use in the ceramer compositions of the present invention, it isdesirable to match the pH of the sol with that of the curable binderprecursor in order to minimize the tendency of the colloids of the solto flocculate when the sol and the curable binder precursor arecombined. For example, if the sol is acidic, the curable binderprecursor also preferably is acidic. On the other hand, if the sol isbasic, the curable binder precursor also preferably is basic.

In one preferred ceramer embodiment of the present invention to bederived from an aqueous silica sol, it may be desirable to add a minoramount of a water soluble compound such as sodium aluminate (NaAlO₂) tothe sol. Addition of a compound such as sodium aluminate provides a sol,and corresponding ceramer composition, that include both silica colloidsand aluminum oxides. Use of an additive oxide such as aluminum oxidemakes it easier to obtain homogeneous ceramer compositions, improvedabrasion resistance, and improved adhesion in wet or dry environments.This is believed to be attributable to the enhanced hydrolytic stabilityof ceramer composites including silica colloids and aluminum oxides.

The sols may include counterions in order to counter the surface chargeof the colloids. Depending upon pH and the kind of colloids being used,the surface charges on the colloids can be negative or positive. Thus,either cations or anions are used as counter ions. Examples of cationssuitable for use as counter ions for negatively charged colloids includeNa⁺, K⁺, Li⁺, a quaternary ammonium cation such as NR′⁴⁺, (wherein eachR′ may be any monovalent moiety, but is preferably H or lower alkyl suchas CH₃), combinations of these, and the like. Examples of counter anionssuitable for use as counter ions for positively charged colloids includeHSO₃ ⁻ and R-COO⁻ where R represents an alkyl carboxylate.

As one option, suitable curable binder precursors can be selected fromany curable thermoplastic or thermosetting polymer that containsmoieties capable of crosslinking with the R_(c) (refer to Formula (12))moiety of the crosslinkable silane component. Examples of such polymersinclude polyurethane, polycarbonate, polyester, polyamide, polyimide,phenoxy, phenolic resin, cellulosic resin, polystyrene, styrenecopolymer, poly(meth)acrylate, epoxy, silicone resin, combination ofthese, and the like. As another option, the curable binder precursor canbe in the form of prepolymeric materials which can be copolymerized orhomopolymerized in situ after the ceramer composition has been coatedonto a substrate.

As one example of an approach using prepolymeric materials, the curablebinder precursor may contain one or more free-radically-curablemonomers, oligomers, polymers, or combinations of these having pendantfree-radically-curable functionality which allows the materials topolymerize or crosslink using a source of curing energy such as electronbeam radiation, ultraviolet radiation, visible light, and the like.Preferred free-radically-curable monomers, oligomers, or polymers eachinclude one or more free-radically-curable, carbon-carbon double bondssuch that the average functionality of such materials is greater thanone free-radically-curable carbon-carbon double bond per molecule.Materials having such moieties are capable of copolymerization orcrosslinking with each other via such carbon-carbon double bondfunctionality.

Generally, the term “monomer” as used herein refers to a single, oneunit molecule capable of combination with itself or other monomers toform oligomers or polymers. The term “oligomer” refers to a compoundthat is a combination of 2 to 20 monomers. The term “polymer” refers toa compound that is a combination of 21 or more monomers.

Generally, ceramer compositions including oligomeric or polymericfree-radically-curable binder precursors tend to have higher viscositiesthan ceramer compositions including only monomericfree-radically-curable binder precursors. Accordingly, in applicationsinvolving techniques such as spin coating or the like in which it isdesirable for the ceramer composition to have a low viscosity, e.g., aviscosity of less than 200 centipoise measured at 25° C. using aBrookfield viscometer with any suitable spindle operated at a spindlespeed in the range from 20 to 50 rpm, it is preferred that at least 50%,by weight, more preferably substantially all, of any prepolymeric binderprecursors are monomeric free-radically-curable binder precursors.

Free-radically-curable monomers suitable in the practice of the presentinvention are preferably selected from combinations of mono, di, tri,tetra, penta, and hexafunctional free-radically-curable monomers.Various amounts of the mono, di, tri, tetra, penta, and hexafunctionalfree-radically-curable monomers may be incorporated into the presentinvention, depending upon the desired properties of the final ceramercoating.

For example, in order to provide ceramer coatings with higher levels ofabrasion and impact resistance, it is desirable for the ceramercomposition to include one or more multifunctionalfree-radically-curable monomers, and preferably at least both di- andtri-functional free-radically-curable monomers, such that thefree-radically-curable monomers incorporated into the ceramercomposition have an average free-radically-curable functionality permolecule of greater than 1. Preferred ceramer compositions of thepresent invention may include about 1 to about 35 parts by weight ofmonofunctional free-radically-curable monomers, 0 to about 75 parts byweight of difunctional free-radically-curable monomers, about 1 to about75 parts by weight of trifunctional free-radically-curable monomers, 0to about 75 parts by weight of tetrafunctional free-radically-curablemonomers, 0 to about 75 parts by weight of pentafunctionalfree-radically-curable monomers, and 0 to about 75 parts by weight ofhexafunctional free-radically-curable monomers, subject to the provisothat the free-radically-curable monomers have an average functionalityof greater than 1, preferably 1.1 to 4, more preferably 1.5 to 3.

One representative class of monofunctional free-radically-curablemonomers suitable in the practice of the present invention includescompounds in which a carbon-carbon double bond is directly or indirectlylinked to an aromatic ring. Examples of such compounds include styrene,alkylated styrene, alkoxy styrene, free-radically-curable naphthalene,alkylated vinyl naphthalene, alkoxy vinyl naphthalene, combinations ofthese, and the like. Another representative class of monofunctional,free-radically-curable monomers includes compounds in which acarbon-carbon double bond is attached to an cycloaliphatic,heterocyclic, or aliphatic moiety such as 5-vinyl-2-norbomene, 4-vinylpyridine, 2-vinyl pyridine, 1-vinyl-2-pyrrolidinone, 1-vinylcaprolactam, 1-vinylimidazole, N-vinyl formamide, and the like.

Another representative class of such monofunctionalfree-radically-curable monomers include (meth)acrylate functionalmonomers that incorporate moieties of the formula:

wherein R⁸ is a monovalent moiety, such as hydrogen, halogen, methyl, orthe like. Representative examples of such monomers include, linear,branched, or cycloaliphatic esters of (meth)acrylic acid containing from1 to 20, preferably 1 to 8, carbon atoms, such as methyl (meth)acrylate,n-butyl (meth)acrylate, t-butyl (meth)acrylate, ethyl (meth)acrylate,isopropyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; vinyl estersof alkanoic acids wherein the alkyl moiety of the alkanoic acids contain2 to 20, preferably 2 to 4, carbon atoms and may be linear, branched, orcyclic; isobomyl (meth)acrylate; vinyl acetate; allyl (meth)acrylate,and the like.

Such (meth)acrylate functional monomers may also include other kinds ofreactive functionality such as hydroxyl functionality, nitrilefunctionality, epoxy functionality, carboxylic functionality, thiolfunctionality, amine functionality, sulfonyl functionality, combinationsof these, and the like. Representative examples of suchfree-radically-curable compounds include glycidyl (meth)acrylate,(meth)acrylonitrile, β-cyanoethyl-(meth)acrylate, 2-cyanoethoxyethyl(meth)acrylate, p-cyanostyrene, p-(cyanomethyl)styrene, an ester of anα,β-unsaturated carboxylic acid with a diol, e.g., 2-hydroxyethyl(meth)acrylate, or 2-hydroxypropyl (meth)acrylate;1,3-dihydroxypropyl-2-(meth)acrylate;2,3-dihydroxypropyl-1-(meth)acrylate; an adduct of an α,β-unsaturatedcarboxylic acid with caprolactone; an alkanol vinyl ether such as2-hydroxyethyl vinyl ether; 4-vinylbenzyl alcohol; allyl alcohol;p-methylol styrene, (meth)acryloyloxyethyl trimethyl ammonium chloride,(meth)acrylamidopropyl trimethylammonium chloride, vinylbenzyltrimethylammonium chloride, 2-hydroxy-3-allyloxypropyl trimethylammoniumchloride, (meth)acryloxypropyl dimethylbenzylammonium chloride,dimethylaminoethyl (meth)acrylate, vinylbenzyl trimethylammoniumchloride, N-(3-sulfopropyl)-N-(meth)acryloxyethyl-N,N-dimethylammoniumbetaine, 2-[(meth)acryloxy]ethyl trimethylammonium methosulfate,N-(3-sulfopropyl)-N-(meth)acrylamidopropyl-N, N-dimethylammoniumbetaine, N,N-dimethylamino (meth)acrylate, (meth)acryloyloxyethyl acidphosphate, (meth)acrylamidopropyl sodium sulfonate, sodium styrenesulfonate, styrene sulfonic acid, (meth)acrylic acid, maleic acid,fumaric acid, maleic anhydride, vinyl sulfonic acid,2-(meth)acrylamide-2-methyl-1-propanesulfonic acid, maleic anhydride,mixtures thereof, and the like.

Another class of monofunctional, free-radically-curable monomers thatmay optionally be used in the practice of the present invention, but isin no way required, includes one or more N,N-disubstituted(meth)acrylamides. Use of an N,N-disubstituted (meth)acrylamide providesnumerous advantages. For example, the use of this kind of monomerprovides ceramer coatings which show improved adhesion to polycarbonatesubstrates. Further, use of this kind of monomer also provides ceramercoatings with improved weatherability and toughness. Preferably, theN,N-disubstituted (meth)acrylamide has a molecular weight in the rangefrom about 99 to about 500, preferably from about 99 to about 200, inorder to minimize the tendency, if any, of the colloidal inorganic oxideto flocculate and precipitate out of the ceramer composition.

The N,N-disubstituted (meth)acrylamide monomers generally have theformula:

wherein R⁹ and R¹⁰ are each independently hydrogen, a (C₁-C₈)alkyl group(linear, branched, or cyclic) optionally having hydroxy, halide,carbonyl, and amido functionalities, a (C₁-C₈)alkylene group optionallyhaving carbonyl and amido functionalities, a (C₁-C₄)alkoxymethyl group,a (C₄-C₁₈)aryl or heteroaryl group, a (C₁-C₃)alk(C₄-C₁₈)aryl group, or a(C₄-C₁₈)heteroaryl group; with the proviso that only one of R⁹ and R¹⁰is hydrogen; and R¹¹ is hydrogen, a halogen, or a methyl group.Preferably, R⁹ is a (C₁-C₄)alkyl group; R¹⁰ is a (C₁-C₄)alkyl group; andR¹¹ is hydrogen, or a methyl group. R⁹ and R¹⁰ can be the same ordifferent. More preferably, each of R⁹ and R¹⁰ is CH₃, and R¹¹ ishydrogen.

Examples of such suitable (meth)acrylamides areN-(3-bromopropion-amidomethyl) acrylamide, N-tert-butylacrylamide,N,N-dimethylacrylamide, N,N-diethylacrylamide,N-(5,5-dimethylhexyl)acrylamide, N-(1,1-dimethyl-3-oxobutyl)acrylamide,N-(hydroxymethyl)acrylamide, N-(isobutoxymethyl)acrylamide,N-isopropylacrylamide, N-methylacrylamide, N-ethylacrylamide,N-methyl-N-ethylacrylamide, N-(fluoren-2-yl)acrylamide,N-(2-fluorenyl)-2-methylacrylamide, 2,3-bis(2-furyl)acrylamide,N,N′-methylene-bis acrylamide. A particularly preferred (meth)acrylamideis N,N-dimethyl (meth)acrylamide.

Other examples of free-radically-curable monomers include alkenes suchas ethene, 1-propene, 1-butene, 2-butene (cis or trans), compoundsincluding an allyloxy moiety, and the like.

Multifunctional (meth)acrylate compounds suitable for use in the curablebinder precursor are commercially available from a number of differentsuppliers. Alternatively, such compounds can be prepared using a varietyof well known reaction schemes. For example, according to one approach,a (meth)acrylic acid or acyl halide or the like is reacted with a polyolhaving at least two, preferably 2 to 6, hydroxyl groups. This approachcan be represented by the following schematic reaction scheme which, forpurposes of illustration, shows the reaction between acrylic acid and atriol:

This reaction scheme as illustrated provides a trifunctional acrylate.To obtain di, tetra, penta, or hexa functional compounds, correspondingdiol, tetrols, pentols, and hexols could be used in place of the triol,respectively.

According to another approach, a hydroxy or amine functional(meth)acrylate compound or the like is reacted with a polyisocyanate, orisocyanurate, or the like having 2 to 6 NCO groups or the equivalent.This approach can be represented by the following schematic reactionscheme which, for purposes of illustration, shows the reaction betweenhydroxyethyl acrylate and a triisocyanate:

wherein W is

This reaction scheme as illustrated provides a trifunctional(meth)acrylate. To obtain di, tetra, penta, or hexa functionalcompounds, corresponding multifunctional isocyanates could be used inplace of the triisocyanate, respectively.

A preferred class of multifunctional (meth)acryl functional compoundsincludes one or more multifunctional, ethylenically unsaturated estersof (meth)acrylic acid and may be represented by the following formula:

wherein R¹² is hydrogen, halogen or a (C₁-C₄)alkyl group; R¹³ is apolyvalent organic group having m valencies and can be cyclic, branched,or linear, aliphatic, aromatic, or heterocyclic, having carbon,hydrogen, nitrogen, nonperoxidic oxygen, sulfur, or phosphorus atoms;and z is an integer designating the number of acrylic or methacrylicgroups in the ester and has a value of 2 to 7. Preferably, R¹² ishydrogen, methyl, or ethyl, R¹³ has a molecular weight of about 14 to100, and m has a value of 2 to 6. More preferably, z has a value of 2 to5, most preferably 3 to 4. Where a mixture of multifunctional acrylatesor methacrylates are used, z preferably has an average value of about1.05 to 3.

Specific examples of suitable multifunctional ethylenically unsaturatedesters of (meth)acrylic acid are the polyacrylic acid or polymethacrylicacid esters of polyhydric alcohols including, for example, the diacrylicacid and dimethylacrylic acid ester of aliphatic diols such asethyleneglycol, triethyleneglycol, 2,2-dimethyl-1,3-propanediol,1,3-cyclopentanediol, 1-ethoxy-2,3-propanediol,2-methyl-2,4-pentanediol, 1,4-cyclohexanediol, 1,6-hexamethylenediol,1,2-cyclohexanediol, 1,6-cyclohexanedimethanol; the triacrylic acid andtrimethacrylic acid esters of aliphatic triols such as glycerin,1,2,3-propanetrimethanol, 1,2,4-butanetriol, 1,2,5-pentanetriol,1,3,6-hexanetriol, and 1,5,10-decanetriol; the triacrylic acid andtrimethacrylic acid esters of tris(hydroxyethyl) isocyanurate; thetetraacrylic and tetramethacrylic acid esters of aliphatic tetraols,such as 1,2,3,4-butanetetraol, 1,1,2,2,-tetramethylolethane,1,1,3,3-tetramethylolpropane, and pentaerythritol triacrylate; thepentaacrylic acid and pentamethacrylic acid esters of aliphatic pentolssuch as adonitol; the hexaacrylic acid and hexamethacrylic acid estersof hexanols such as sorbitol and dipentaerythritol; the diacrylic acidand dimethacrylic acid esters of aromatic diols such as resorcinol,pyrocatechol, bisphenol A, and bis(2-hydroxyethyl) phthalate; thetrimethacrylic acid ester of aromatic triols such as pyrogallol,phloroglucinol, and 2-phenyl-2,2-dimethylolethanol; and the hexaacrylicacid and hexamethacrylic acid esters of dihydroxy ethyl hydantoin; andmixtures thereof.

In addition to the fluoro/silane component, the crosslinkable silanecomponent, the curable binder precursor, and the colloidal inorganicoxide, the ceramer composition may further include a solvent and otheroptional additives. For example, if desired, the ceramer composition mayinclude a solvent to reduce the viscosity of the ceramer composition inorder to enhance the ceramer coating characteristics. The appropriateviscosity level depends upon various factors such as the coatingthickness, application technique, and the type of substrate materialonto which the ceramer composition is applied. In general, the viscosityof the ceramer composition at 25° C. is about 1 to about 200 centipoise,preferably about 3 to about 75 centipoise, more preferably about 4 toabout 50 centipoise, and most preferably about 5 to about 20 centipoisewhen measured using a Brookfield viscometer with a No. 2 cv spindle at aspindle speed of 20 rpm. In general, sufficient solvent is used suchthat the solids content of the ceramer composition is about 5 to about95%, preferably about 10 to about 50%, more preferably about 15 to about30%, by weight solids.

The solvent is selected to be compatible with the other componentsincluded in the ceramer composition. As used in this context,“compatible” means that there is minimal phase separation between thesolvent and the other components. Additionally, the solvent should beselected such that the solvent does not adversely affect the curingproperties of the ceramer composition or attack the material of thesubstrate. Furthermore, the solvent should be selected such that it hasan appropriate drying rate. That is, the solvent should not dry tooslowly, which would slow down the process of making a coated substrate.It should also not dry too quickly, which could cause defects such aspin holes or craters in the resultant ceramer coating. The solvent canbe an organic solvent, water, or combinations thereof. Representativeexamples of suitable solvents include lower alcohols such as ethanol,methanol, isopropyl alcohol, and n-butanol; ketones such as methyl ethylketone and methyl isobutyl ketone; glycols; glycol ethers; combinationsthereof, and the like. Most preferably, the solvent is isopropanol.Using the procedure described below for making a ceramer composition,the solvent may also include a small amount, e.g. about 2% by weight, ofwater.

The ceramer compositions of the present invention also may include aleveling agent to improve the flow or wetting of the ceramer compositiononto the substrate. If the ceramer composition does not properly wet thesubstrate, this can lead to visual imperfections (e.g., pin holes orridges) in the ceramer coating. Examples of leveling agents include, butare not limited to, alkylene oxide terminated polysiloxanes such as thatavailable under the trade designation “DOW 57” (a mixture of dimethyl-,methyl-, and (polyethylene oxide acetate-capped) siloxane) from DowCorning, Midland, Michigan, and fluorochemical surfactants such as thoseavailable under the trade designations “FC430” and “FC431” fromMinnesota Mining and Manufacturing Company Co., St. Paul, Minn. Theceramer composition can include an amount of a leveling agent effectiveto impart the desired result. Preferably, the leveling agent is presentin an amount up to about 3% by weight, and more preferably about 0.5 toabout 1%, based on the total weight of the ceramer composition solids.It should be understood that combinations of different leveling agentscan be used if desired.

During the manufacture of an abrasion resistant, ceramer coating of thetype including a free-radically-curable binder precursor, the coatedceramer composition preferably is exposed to an energy source, e.g.,radiation, which initiates the curing process of the ceramer coating.This curing process typically occurs via a free radical mechanism, whichcan require the use of a free radical initiator (simply referred toherein as an initiator, e.g., a photoinitiator or a thermal initiator)depending upon the energy source used. If the energy source is anelectron beam, the electron beam generates free radicals and noinitiator is typically required. If the energy source is ultravioletlight, or visible light, an initiator is often required. When theinitiator is exposed to one of these energy sources, the initiatorgenerates free radicals, which then initiates the polymerization andcrosslinking.

Examples of suitable free radical initiators that generate a freeradical source when exposed to thermal energy include, but are notlimited to, peroxides such as benzoyl peroxide, azo compounds,benzophenones, and quinones. Examples of photoinitiators that generate afree radical source when exposed to visible light radiation include, butare not limited to, camphorquinones/alkyl amino benzoate mixtures.Examples of photoinitiators that generate a free radical source whenexposed to ultraviolet light include, but are not limited to, organicperoxides, azo compounds, quinones, benzophenones, nitroso compounds,acryl halides, hydrozones, mercapto compounds, pyrylium compounds,triacrylimidazoles, bisimidazoles, chloroalkytriazines, benzoin, benzoinmethyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoinisobutyl ethers and methylbenzoin, diketones such as benzil anddiacetyl, phenones such as acetophenone,2,2,2-tri-bromo-1-phenylethanone, 2,2-diethoxyacetophenone,2,2-dimethoxy-2-phenylacetophenone,2,2,2,-tribromo-1(2-nitrophenyl)ethanone, benzophenone,4,4-bis(dimethyamino)benzophenone, and acyl phosphates. Examples ofcommercially available ultraviolet photoinitiators include thoseavailable under the trade designations “IRGACURE™ 184”(1-hydroxycyclohexyl phenyl ketone), “IRGACURE™ 361” and “DAROCUR™ 1173”(2-hydroxy-2-methyl-1-phenyl-propan-1-one) from Ciba-Geigy. Typically,if used, an amount of an initiator is included in the ceramercomposition to effect the desired level and rate of cure. Preferably,the initiator is used in an amount of about 0.1 to about 10%, and morepreferably about 2 to about 4% by weight, based on the total weight ofthe ceramer composition without solvent. It should be understood thatcombinations of different initiators can be used if desired.

In addition to the initiator, the ceramer composition of the presentinvention can include a photosensitizer. The photosensitizer aids in theformation of free radicals that initiate curing of the curable binderprecursors, especially in an air atmosphere. Suitable photosensitizersinclude, but are not limited to, aromatic ketones and tertiary amines.Suitable aromatic ketones include, but are not limited to, benzophenone,acetophenone, benzil, benzaldehyde, and o-chlorobenzaldehyde, xanthone,thioxanthone, 9,10-anthraquinone, and many other aromatic ketones.Suitable tertiary amines include, but are not limited to,methyldiethanolamine, ethyldiethanolamine, triethanolamine,phenylmethyl-ethanolamine, dimethylaminoethylbenzoate, and the like.Typically, if used, an amount of photosensitizer is included in theceramer compositions to effect the desired level and rate of cure.Preferably, the amount of photosensitizer used in the ceramercompositions of the present invention is about 0.01 to about 10%, morepreferably about 0.05 to about 5%, and most preferably about 0.25 toabout 3% by weight, based on the total weight of the ceramer compositionwithout solvent. It should be understood that combinations of differentphotosensitizers can be used if desired.

Polymeric materials are known to degrade by a variety of mechanisms.Common additives that can offset this are known as stabilizers,absorbers, antioxidants, and the like. The ceramer compositions of thepresent invention can include one or more of the following: ultravioletstabilizer, ultraviolet absorber, ozone stabilizer, and thermalstabilizer/antioxidant.

An ultraviolet stabilizer or ultraviolet absorber improvesweatherability and reduces the “yellowing” of the abrasion resistant,ceramer coating with time. An example of an ultraviolet stabilizerincludes that available under the trade designation “TINUVIN™ 292”(bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate) and an example of anultraviolet absorber includes that available under the trade designation“TINUVIN™ 1130” (hydroxyphenyl benzotriazole), both of which areavailable from Ciba-Geigy. The ceramer composition can include an amountof either an ultraviolet stabilizer or an ultraviolet absorber to impartthe desired result. Preferably, the ultraviolet stabilizer or absorberis present in an amount up to about 10% by weight, and more preferablyabout 1 to about 5%, based on the total weight of the ceramercomposition without solvent. It should be understood that combinationsof different ultraviolet stabilizers and absorbers can be used ifdesired.

An ozone stabilizer protects against degradation resulting from reactionwith ozone. Examples of ozone stabilizers include, but are not limitedto, hindered amines such as that available under the trade designation“IRGANOX™ 1010” available from Ciba-Geigy and phenoltriazinecommercially available from Aldrich. The ceramer composition can includean amount of an ozone stabilizer to impart the desired result.Preferably, the ozone stabilizer is present in an amount up to about 1%by weight, more preferably about 0.1 to about 1.0%, and most preferablyabout 0.3 to about 0.5%, based on the total weight of the ceramercomposition without solvent. It should be understood that combinationsof different ozone stabilizers can be used if desired.

A thermal stabilizer/antioxidant reduces the amount of yellowing as aresult of weathering. Examples of such materials include, but are notlimited to, low melting hindered phenols and triesters. Specificexamples include 2,6-di-tert-butyl-4-methylphenol commercially availableunder the trade designation “ULTRANOX™ 226” antioxidant from Borg WarnerChemicals, Inc., Parkersburg, N.Y.; octadecyl3,5-di-tert-butyl-4-hydroxycinnamate commercially available under thetrade designations “ISONOX™ 132” antioxidant (Schenectady Chemicals,Inc., Schenectady, N.Y.) or “VANOX™ 1320” antioxidant (Vanderbilt Co.,Inc., Norwalk, Conn.). The ceramer composition can include sufficientthermal stabilizer/antioxidant to impart the desired result. Preferably,the thermal stabilizer/antioxidant is present in an amount up to about3% by weight, and more preferably about 0.5 to about 1%, based on thetotal weight of the ceramer composition without solvent. It should beunderstood that combinations of different thermalstabilizers/antioxidants can be used if desired.

According to one approach, a ceramer composition of the presentinvention is prepared by combining ingredients including a fluoro/silanecomponent, a crosslinkable silane component, a curable binder precursor,and a colloidal inorganic oxide. The fluoro/silane component may becombined with a first admixture containing a colloidal inorganic oxideand a curable binder precursor in the presence of a crosslinkable silanecomponent. The fluoro/silane component may be premixed with thecrosslinkable silane component to form a second admixture, which secondadmixture is then combined with the first admixture to form a thirdadmixture, namely the ceramer composition. The crosslinkable silanecomponent may also be premixed with the first admixture to provide afourth admixture which can then be combined with the fluoro/silanecomponent to form the ceramer composition.

The fluoro/silane component, first admixture and crosslinkable silanecomponent are combined under conditions such that at least a portion ofthe colloidal inorganic oxides is surface treated by the fluoro/silanecomponent. Preferably, once so combined, the hydrolyzable silanemoieties of the fluoro/silane component and the crosslinkable silanecomponent are allowed to react with and thereby functionalize (surfacetreat) the colloidal inorganic oxides with pendant R_(c) and R_(f)functionality. By incorporating the fluoro/silane component into theceramer composition in this manner, the resultant ceramer compositionremains optically clear and, therefore, is especially useful for formingoptically clear ceramer coatings.

The ceramer composition is then stripped, e.g., heated under vacuum toremove substantially all of the water. For example, removing about 98%of the water, thus leaving about 2% water in the ceramer composition,has been found to be suitable. When the curable binder precursorcontains free-radically-curable prepolymers, the resultant dried ceramercomposition is a clear liquid. As soon as substantially all of the wateris removed, an organic solvent of the type described above is added, ifdesired, in an amount such that the ceramer composition preferablyincludes from about 5% to about 95% by weight solids, more preferablyfrom about 10% to about 50% by weight solids and most preferably fromabout 15% to about 30% by weight solids.

The resultant ceramer composition is then coated onto any substrate forwhich it is desired to improve one or more of abrasion resistance,impact resistance or stain resistance. Examples of such substratesinclude any and all thermosetting or thermoplastic items such as cameralenses, eyeglass lenses, binocular lenses, automobile windows and bodypanels as an automotive topcoat, building windows, bakeware, trainwindows, boat windows, aircraft windows, vehicle headlamps andtaillights, display cases, eyeglasses, watercraft hulls, overheadprojectors, stereo cabinet doors, stereo covers, furniture, bus stationplastic, television screens, computer screens, watch covers, instrumentgauge covers, optical and magneto optical recording disks, graphicdisplays, and the like. Adhesion of the ceramer coating to the substratemay vary depending on the particular substrate and on other factors suchas whether the substrate is primed, oriented during manufacture(unoriented or oriented axially or biaxially) or otherwise modified.

The ceramer compositions of the present invention may also be applied toanimal skin products such as leather, and to synthetic leather productsto protect such products from stains, abrasion, scuffing, cracking, andwear. Typically, the ceramer composition is applied to these productsusing spray, brush, roll, or transfer coating methods.

Any suitable coating technique can be used for applying the ceramercomposition to the substrate, depending upon the nature of thesubstrate, the viscosity of the ceramer composition, and the like.Examples of suitable coating techniques include spin coating, gravurecoating, flow coating, spray coating, coating with a brush or roller,screen printing, knife coating, curtain coating, slide curtain coating,extrusion, squeegee coating, and the like. Typical protective ceramercoatings of the present invention have a thickness in the range fromabout 1 micron to about 100 microns, preferably about 2 to about 50microns, more preferably about 4 to about 9 microns. Generally, ceramercoatings that are too thin may not have sufficient abrasion or impactresistance, and tend to run, thereby causing a waste of material.Ceramer films that are too thick may have a greater tendency to crack.

After coating, the solvent can be flashed off with heat or allowed toevaporate under ambient conditions. If radiation curable, the coatedceramer composition is then cured by irradiation with a suitable form ofenergy, such as visible light, ultraviolet light or electron beamradiation. Irradiating with ultraviolet light in ambient conditions ispresently preferred due to the relative low cost and speed of thiscuring technique. Irradiation causes the curable binder precursor andthe surface treated, colloidal inorganic oxides to crosslink together toform a ceramer coating containing a polymer matrix having the colloidalinorganic oxides, and any optional additives, interspersed in thepolymer matrix. The resultant ceramer-coated substrate is therebyprotected against stains, abrasion, and impact.

The present invention will now be further described with reference tothe following examples.

EXAMPLES Test Methods

Test Procedure I: Taber Abrasion Test on Plastic

This test measures the Taber abrasion of the ceramer composition whencoated on a substrate and was performed according to ASTM D1044(Standard Method for Resistance of Transparent Plastics to SurfaceAbrasion), the disclosure of which is incorporated herein by reference.Briefly, the test method involved abrading a sample on a TABER ABRASER™tester for 100, 300 and 500 cycles using a 500 gram load with a CS-10Fwheel at room temperature. After each cycle of exposure to the abrasivewheels the percent change in haze was measured.

Test Procedure II: Warm Water Adhesion Test

This test was designed to test the ceramer composition's durability whencoated on a substrate and submersed in water at elevated temperatures.The sample was completely submerged in water at the stated temperaturefor the stated time period. Specifically, the samples were submerged inwater baths at about 60° C. for 11 and 13 days, at about 71° C. for 6and 8 days and at about 82° C. for 3 and 5 days. At the end of thestated time period, the samples were removed, examined for anydelamination and subjected to a Cross Hatch Adhesion Test (TestProcedure IV described below) and to a Tape Snap Test (Test Procedure Vdescribed below).

Test Procedure III: Weatherability

This test assesses the ability of the ceramer composition, when coatedon a substrate, to withstand weathering conditions (e.g., sunlight). Thetest was conducted according to ASTM Test Standard G-26-88, Type B, BH(Standard Practice for Operating Light Exposure Apparatus (Xenon-ArcType) with and without Water for Exposure of Nonmetallic Materials), thedisclosure of which is incorporated by reference herein.

Briefly, a sample was exposed to a 6500 Joule/second xenon burner filterthrough borosilicate inner and outer filters at 0.35W/m² in a WaterCooled Xenon Arc Model 65XWWR Weathering Chamber, available from AtlasElectric Devices Co. (Chicago, Ill.) for repetitive cycles of 102minutes at about 63° C. followed by 18 minutes with a water spray. Toprovide a ceramer coating passing this test for a particular substrate,the ceramer coating must be capable of withstanding at least 1000 hoursof exposure under these conditions with no significant yellowing,whitening, or other discoloration.

Undesirable results obtained from this weathering test include, inparticular, whitening, delamination, and “checks”, which areimperfections in the form of slight inclusions in the coating.

Test Procedure IV: Cross Hatch Adhesion Test

The test method assesses the adhesion of coating films to substrates byapplying and removing pressure-sensitive adhesive tape over cuts made ina film of the coating composition. A crosshatch pattern with 3 cuts ineach direction was made in the coating on the substrate. Then apressure-sensitive adhesive tape was applied over the crosshatch andremoved. Adhesion was evaluated by comparing descriptions andillustrations. The cutting tool was a sharp razor blade, scalpel, knifeor other cutting device which had a cutting edge in good condition. Acutting guide was used to ensure straight cuts. The tape was 1 inch (25mm) wide semi transparent pressure-sensitive adhesive tape with anadhesion strength of 36 plus or minus 2.5 oz/in. (40 plus or minus 2.8g/mm) when tested in accordance with ASTM Test Method B 1000incorporated by reference herein in its entirety.

An area free of blemishes and minor surface imperfections on the coatingwas selected. Care was taken to ensure that the surface was clean anddry. Extremes in temperature or relative humidity which may affect theadhesion of the tape or the coating were avoided. Two sets of threeparallel 20 mm long cuts were made in the coating, with one set orientedat 90° to cuts in the other set and the sets intersecting near themiddle of the test panel. The cuts were made in one steady motion topenetrate through the coating to the substrate, leaving the substratevisible through the coating. After cutting, the film was lightly brushedto remove detached flakes or ribbons of coatings. A piece of tape 75 mmlong was removed from the roll and placed with the center of tape at theintersection of the cuts with the tape running in the same direction asone set of the cuts. The tape was smoothed in place with finger in thearea of the cuts and then rubbed firmly with an eraser on the end of apencil. Within 90 seconds (plus or minus 30 seconds) of application, thetape was removed by creasing a free end and pulling it off rapidly atabout 180°, without jerking the tape back upon itself. The cut area wasthen inspected for removal of coating from the substrate and rated foradhesion according to the following scale: A coating was designated“pass” if:

the edges of the cuts are completely smooth; none of the squares of thelattice is detached; or

small flakes of the coating are detached at intersections; (less than 5%of the area is affected); or

small flakes of the coating are detached along edges and atintersections of cuts; (the area affected is 5 to 15% of the lattice).

The coating was designated “fail” if:

the coating has flaked along the edges and on parts of the squares; (thearea affected is 15 to 35% of the lattice); or

the coating has flaked along the edges of cuts in large ribbons andwhole squares have detached; (the area affected is 35 to 65% of thelattice).

Test Procedure V: Tape Snap Test

A section of adhesive tape was affixed to the surface of the coatingwith the end of the tape overlapping the edge of the sheet. The tape wasthen “snapped” off by pulling it rapidly at 90° to the surface of thecoating, and the coating visually inspected for evidence ofdelamination. A coating was designated “pass” if minor or no evidence ofdelamination was found.

Test Procedure VI: Taber Abrasion Test on Leather

This test measures the Taber abrasion of the ceramer composition whencoated on a leather substrate and was performed according to ASTM D3884,the disclosure of which is incorporated herein by reference. This testmethod measures the abrasion resistance of the surface coating onleather and synthetic leathers using a rotary rubbing action undercontrolled pressure. The Taber abrasion machine used was Model number5130 available from Taber Industries, Tonawanda, N.Y. The samples werecut to about 103±3 millimeters with a 7±1 millimeter hole punched in thecenter of the test sample. The samples were attached to the Taber discwith S-36 cardboard backer (available from Taber Industries). Thetesting was conducted using conditioned H-22 abrasive wheels with 1000gram weights. A sample failed when a wear area of about 2 millimetersdepth was observed.

Example 1

56.2 Parts by weight of the curable binder precursor PETA(pentaerythritol triacrylate) was heated to about 49° C. in a one literflask. 35.2 Parts by weight silica (88 parts of 40% solids, 20nanometers average particle size, commercially available from NalcoCorp., Naperville, Ill., under the trade designation “Nalco 2327”) wereadded to the PETA to form a first admixture. In a separate flask, 7.7parts by weight of the crosslinkable silane component3-methacryloxypropyl-trimethoxysilane, (commercially available fromUnion Carbide under the trade designation “A-174”) were mixed with 0.8parts by weight of fluoro/silane component of Formula (11) (commerciallyavailable from Minnesota Mining and Manufacturing Company, St. Paul,Minn. under the trade designation “FC-405”) to form a second admixture.The first and second admixtures were then mixed together to form a thirdadmixture. In a weighing tray, 0.15 parts by weight BHT (butylatedhydroxytoluene) and 0.02 parts by weight phenothiazine (both based onthe 56.2 parts by weight PETA) were mixed together and then added to thethird admixture to form a fourth admixture.

The fourth admixture was then “stripped” by subjecting it to a gentlevacuum distillation (100±20 mm Hg) at 52°±2° C. until most of thewater/methanol was removed. A residual amount (a few weight-percent) ofwater remained in the dried product. At the end of the strippingprocess, the admixture was diluted to 50% solids with a 14:1weight-ratio solvent of isopropyl alcohol:distilled water. This 50%solids admixture was further diluted to 25% solids with the same solventmixture. About 0.7 parts by weight photoinitiator (commerciallyavailable from Ciba Geigy Corp., Hawthorne, N.Y., under the tradedesignation “IRGACURE 184”) was also added.

The ceramer composition was then coated onto PMMA(polymethylmethacrylate) and polycarbonate substrates at a thickness ofabout 4 to about 5 micrometers using conventional flow coatingtechniques. Each coated substrate was then flash dried at about 60° C.for 2.5 minutes in an air circulating oven to ensure that the majorityof the isopropanol was driven off. Finally, the coating was cured on aconveyor belt of a UV light processor using a high pressure mercury lamp(Model QC 1202, available from PPG Industries, Plainfield, Ill.). Theprocess conditions were 16.5 meters/minute, 410 volts, energy 90 mJ/cm²,and an air atmosphere.

The resulting ceramer coatings were perfectly clear and adhered to thePMMA and polycarbonate substrates. Furthermore, the coatings passed TestProcedures I, II and III and had excellent shelf stability. After 6months, sols prepared in accordance with the above procedure were clear,with no apparent flocculation.

Example 2

Example 2 was carried out as in Example 1 except that the crosslinkablesilane component was added to the first admixture of PETA and silica,followed by addition of the fluoro/silane component. These steps wereperformed by heating 56.2 parts by weight of PETA to about 49° C. in aone liter flask. 35.2 Parts by weight silica (88 parts by weight of 40%solids NALCO™ 2327) was added to the flask. 7.7 Parts by weight of3-methacryloxypropyl-trimethoxysilane were then added to the flask,followed by addition of 0.8 parts by weight of a fluoro/silane componentof Formula (11). In a weighing tray, 0.15 part by weight BHT and 0.02parts by weight phenothiazine (both based on the 56.2 parts by weightPETA) were mixed together and then added to the flask. The resultingadmixture was then stripped, diluted with solvent, coated onto PMMA andpolycarbonate substrates and cured as in Example 1. The resultingceramer coatings were perfectly clear and adhered to the PMMA andpolycarbonate substrates. Furthermore, the resulting ceramer coatingspassed Test Procedures I, II and III.

Example 3

Example 3 was carried out as in Example 1 except that the fluoro/silanecomponent was first added individually to the first admixture of PETAand silica, followed by addition of the crosslinkable silane component.These steps were performed by heating 56.2 parts by weight of PETA toabout 49° C. in a one liter flask. 35.2 Parts by weight silica (88 partsby weight of 40% solids NALCO 2327) were added to the flask. 0.8 Partsby weight of the fluoro/silane component were then added to the flask,followed by addition of 7.7 parts by weight of3-methacryloxypropyl-trimethoxysilane. In a weighing tray, 0.15 parts byweight BHT and 0.02 parts by weight phenothiazine (both based on the56.2 parts by weight PETA) were mixed together and then added to theflask. The final mixture precipitated. Thus, the composition was notcoatable and the experiment was not completed.

Example 4

Example 4 was carried out as in Example 1 except that 15.6 parts byweight (based on 56.2 parts by weight PETA) of dimethylacrylamide (DMA)was added to the third admixture of Example 1 before addition of themixture of BHT and phenothiazine. The resulting admixture was thenstripped, diluted with solvent, coated onto PMMA and polycarbonatesubstrates and cured as in Example 1. The resulting ceramer coatingswere perfectly clear and adhered to the PMMA and polycarbonatesubstrates. Furthermore, the resulting ceramer coatings passed TestProcedures I, II and III and performed as well as the coatings ofExample 1. This example thus shows that DMA may be used in the ceramercompositions of the present invention, if desired, but is not required.

Example 5

Example 5 was prepared as described in Example 1, except asilica/alumina mixture was substituted for the silica. Thus, 56.2 partsby weight of PETA were preheated to about 49° C. and then combined with35.3 parts by weight of silica (88 parts by weight of 40% solids NALCO™2327, 20 nm) and 1 part by weight sodium aluminate (NaAlO₂) to form afirst admixture. A second admixture of 7.8 parts by weight of A-174 and0.8 parts by weight of the compound of Formula (11) was prepared andadded to the first admixture with stirring to form a third admixture. Ina weighing tray, 0.15 parts by weight BHT and 0.02 parts by weightphenothiazine (both based on the 56.2 parts by weight PETA) were mixedtogether and then added to the third admixture to form a fourthadmixture.

The fourth admixture was then stripped, diluted with solvent, coatedonto PMMA and polycarbonate substrates and cured as in Example 1.

Example 6

Example 6 was carried out as described in Example 5, exceptdimethylacrylamide was added to the other ingredients in the secondadmixture. The second admixture contained about 0.7 parts by weight ofA-174, 0.8 parts by weight of the compound of Formula (11) and 8.0 partsby weight of dimethylacrylamide. The ceramer composition was stripped,diluted with solvent, coated onto PMMA and polycarbonate substrates andcured as in Example 1.

Comparative Example A

This ceramer composition contained dimethylacrylamide (DMA) as acomponent of the binder precursor, but no fluoro/silane component.Specifically, 51.5 parts by weight of PETA were heated to about 49° C.32.4 Parts by weight silica (88 parts by weight of 40% solids NALCO2327) were added to the PETA to form a first admixture. In a separateflask, 8.1 parts by weight of 3-methacryloxypropyl-trimethoxysilane weremixed with 8.0 parts by weight DMA to form a DMA-altered secondadmixture. The first admixture was mixed with the DMA-altered secondadmixture to form a third admixture. In a weighing tray, 0. 15 parts byweight BHT and 0.02 parts by weight phenothiazine (both based on the51.5 parts by weight PETA) were mixed together and then added to thethird admixture to form a fourth admixture.

The fourth admixture was then stripped, diluted with solvent, coatedonto PMMA and polycarbonate substrates and cured as in Example 1. Likethe ceramer coating of Example 1, the ceramer coatings of thiscomparative example were perfectly clear, adhered to the PMMA andpolycarbonate substrates, and passed Test Procedures I, II and III. Thusin these tested respects, a composition of the invention performedcomparably to a ceramer made using DMA but no fluoro/silane component.

Comparative Example B

Comparative Example B was prepared as described in Example 2 except thatno fluoro/silane component was added. 56.2 Parts by weight of PETA wereheated to about 49° C. (120° F.) in a one liter flask. 35.2 Parts byweight silica (88 parts by weight of 40% solids NALCO 2327) were addedto the PETA to form a first admixture. 7.7 Parts by weight of3-methacryloxypropyl-trimethoxysilane were then added to the flask,followed by the addition of 15.6 parts by weight DMA (based on 56.2parts by weight PETA). In a weighing tray, 0.15 parts by weight BHT and0.02 parts by weight phenothiazine (both based on the 56.2 parts byweight PETA) were mixed together and then added to the flask.

The resulting admixture was then stripped, diluted with solvent, coatedonto PMMA and polycarbonate substrates and cured as in Example 2. Likethe ceramer coating of Example 2, the ceramer coatings of thiscomparative example were perfectly clear, adhered to the PMMA andpolycarbonate substrates, and passed Test Procedures I, II and III. Thusin these tested respects, a composition of the invention performedcomparably to a ceramer made using DMA but no fluoro/silane component.

Comparative Example C

Comparative Example C was a hardcoating prepared using commerciallyavailable coating material from Cyro Corp., Rockaway, N.J., under thetrade designation “CYRO AR”.

Comparative Example D

A mixture was prepared as described in Comparative Examples A and B,omitting DMA. The resulting mixture coagulated on stripping.

Summary of Results

The ceramer coatings described above were evaluated using a variety oftest methods. As is illustrated in the following Tables 3 through 10 andin Examples 1-2 and 4, a nonionic fluorochemical containing both afluorinated moiety and a silane moiety (the fluoro/silane component) canbe successfully incorporated into a ceramer sol, without causing colloidflocculation. Ceramer coatings containing such a fluoro/silanecomponent, whether prepared with or without DMA, have surprisingly longshelf lives and excellent stain resistant characteristics (See Examples1 and 4). Additionally, ceramer compositions of the present inventioncan be used to prepare ceramer coatings that exhibit a high level ofabrasion resistance, durability and hardness (See Tables 3-10). Some ofthe coatings shown in Tables 3-10 employed additives whose formulationsare set out in Table 1 and whose ingredients are further identified inTable 2. The amounts of such additives are expressed based on the weightof ceramer solids.

TABLE 1 Additive Components I 0.9 parts by weight “TINUVIN¹ 123” 1.6parts by weight “SANDUVOR² 3058” 2.8 parts by weight “TINUVIN 1130” 2.8parts by weight “TINUVIN 400” II “TINUVIN 292” III 2 parts by weight“TINUVIN 292” 2 parts by weight “TINUVIN 384” IV 1.2 parts by weight“TINUVIN 123” 0.7 parts by weight “SANDUVOR 3058” 2.07 parts by weight“TINUVIN 384” 2.07 parts by weight “TINUVIN 400” ¹TINUVIN, all grades,is commercially available from Ciba-Geigy Corporation, Hawthorne, NY²SANDUVOR, all grades, is commercially available from Clariant Corp,Charlotte, NC

TABLE 2 Trade Name Chemical Name TINUVIN 123bis-(1-octyloxy-2,2,6,6,tetramethyl-4-piperidinyl) sebacate SANDUVOR3058 N-acrylated HALs compound TINUVIN 4001,3-benzenediol,4-[4,6-bis(2,4-dimethyl)-1,3,5- triazin-2-yl] CG TINUVIN292 bis-(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate CG TINUVIN 1130hydroxyphenyl benzotriazole TINUVIN 3843-(2H-benzotriazol-2-YL)-5-(tert-butyl)-4- hydroxybenzenepropanoic acid

TABLE 3 Taber Abrasion Test - Coated on PMMA % HAZE Sample 100 cycles300 cycles 500 cycles Comp. A* 2.6 3.1 4.1 Example 4* 2.0 3.0 3.6 Comp.B 1.4 3.0 3.9 Example 1 1.3 3.1 3.9 Example 4 0.9 2.4 3.2 Comp. A** 1.93.6 4.2 Comp. B** 1.5 2.8 3.7 Example 1** 1.6 3.3 4.1 Example 4** 1.32.9 3.5 Samples denoted with “*” included 4 wt-% of additive III onceramer weight basis. Samples denoted with “**” included 2 wt-% ofadditive II.

TABLE 4 Taber Abrasion Test - Coated on Polycarbonate % HAZE Sample 100cycles 300 cycles 500 cycles Example 1 1.7 3.3 4.1 Example 4 1.3 2.8 3.5Comp. A* 3.1 3.2 3.8 Example 4* 2.8 2.7 3.1 Comp. B 1.3 2.3 3.2 Example1 1.0 2.5 3.2 Example 4 1.0 2.3 3.1 Comp. A** 2.5 2.9 4.4 Comp. B** 3.02.5 3.5 Example 1** 3.0 2.6 3.3 Example 4** 2.7 2.2 3.1 Comp. C. 2.5 3.03.8 Samples denoted with “*” included 6 wt-% of additive IV on a ceramerweight basis. Samples denoted with “**” included 8 wt-% of additive I.

TABLE 5 Warm Water Adhesion Test - Coated on PMMA Sample 11 days @ 60°C. 8 days @ 71° C. 3 days @ 82° C. Example 1 pass Pass pass Example 4pass Pass pass Comp. A* pass Pass pass Example 4* pass Pass pass Samplesdenoted with “*” included 4 wt-% of additive III of a ceramer weightbasis.

TABLE 6 Warm Water Adhesion Test - Coated on PMMA Sample 13 days @ 60°C. 6 days @ 71° C. 5 days @ 82° C. Comp. B pass pass pass Example 1 passpass pass Example 4 pass pass pass Comp. A* pass pass pass Comp. B* passpass pass Example 1* pass pass pass Example 4* pass pass pass Comp. C.pass pass pass Samples denoted with “*” included 2 wt-% of additive IIon a ceramer weight basis.

TABLE 7 Warm Water Adhesion Test - Coated on Polycarbonate Sample 11days @ 60° C. 8 days @ 71° C. 3 days @ 82° C. Comp. A pass pass passExample 1 pass pass pass Example 4 pass pass pass Comp. A* pass passpass Example 4* pass pass pass Samples denoted with “*” included 6 wt-%of additive IV on a ceramer weight basis.

TABLE 8 Warm Water Adhesion Test - Coated on Polycarbonate Sample 13days @ 60° C. 6 days @ 71° C. 5 days @ 82° C. Comp. A pass pass passComp. B pass pass pass Example 1 pass pass pass Example 4 pass pass passComp. A* pass pass delaminated Comp. B* pass pass delaminated Example 1*pass pass delaminated Example 4* pass pass delaminated Comp. C. passpass pass Samples denoted with “*” included 8 wt-% of additive I on aceramer weight basis.

TABLE 9 Weathering Test - Coated on PMMA Sample Hours Example 1 1400 -few small checks Example 4 1400 - few small checks Comp. A 1400+ Example1* 3700 - few long checks Example 4* not done Comp. A* 3515+ Example 11800 - checks, slight whitening Example 4 1800 - checks, slightwhitening Comp. B 1800 - checks, slight whitening Example 1** 2425+Example 4** 2525+ Comp. A** 3515+ Comp. B** 2425+ +denotes that the testis on going Samples denoted with “*” included 4 wt-% of additive III.Samples denoted with “**” included 2 wt-% of additive II.

TABLE 10 Weathering Test - Coated on Polycarbonate Sample Hours Example1 1000 - 20% delamination Example 4 1000 - total delamination Comp. A˜800 Example 1* 2400 - slight delamination Example 4* not done Comp. A*2200 Example 1 ˜750 Example 4 ˜750 Comp. A ˜800 Comp. B ˜900 Example 1**2425 - slight delamination & very small checks Example 4** 2425 - slightdelamination & very small checks Comp. A** ˜2500 Comp. B** 2425 - slightdelamination Samples denoted with “*” included 6 wt-% of additive IV.Samples denoted with “**” included 8 wt-% of additive I.

In the following Examples, coating formulations were prepared as inExample 1 using various inorganic oxides. The coating compositions werecoated onto either acrylic (Cyro-FF™, available from Cyro Inc.) orpolycarbonate (Cyro-ZX™, available from Cyro Inc.) substrates and curedas previously described. The cured coatings were then subjected to theTaber Abrasion Test on Plastic. As a comparative test, acrylic andpolycarbonate sheets coated with a proprietary abrasion-resistantcoating (Cyro-AR¹ m, available from Cyro Inc.) were also tested. Theinorganic oxides used and the results of the abrasion tests are shown inTables 11 and 12.

TABLE 11 % HAZE on Acrylic Inorganic Sample Oxide 100 cycles 300 cycles500 cycles Comp. E Cyro-AR 2.2 4.3 5.7 Example 7 SiO₂/NaAlO₂ 1.3 3.2 4.299:1 Example 8 SiO₂/NaAlO₂ 1.0 2.5 3.4 98:2 Example 9 SiO₂/ZrO₂ 2.3 4.67.6 95:5 Example 10 SiO₂/ZrO₂ 3.2 6.5 9.5 90:10 Example 11 SiO₂/SnO₂ 1.23.2 4.2 95:5

TABLE 12 % HAZE on Polycarbonate Inorganic Sample Oxide 100 cycles 300cycles 500 cycles Comp. F Cyro-AR 2.2 2.9 3.5 Example 12 SiO₂/NAlO₂ 1.02.4 3.4 99:1 Example 13 SiO₂/NaAlO₂ 0.6 1.7 2.5 98:2 Example 14SiO₂/ZrO₂ 1.8 3.6 5.2 95:5 Example 15 SiO₂/ZrO₂ 2.1 4.8 7.1 90:10Example 16 SiO₂/SnO₂ 0.7 2.0 3.0 95:5

As can be seen from the data, all the samples provide good abrasionresistance on both acrylic and polycarbonate substrates. In particular,the coatings containing NaAlO₂ or mixed oxides of SiO₂ and SnO₂ provideimproved abrasion resistance relative to commercially availablecoatings.

Examples 17 to 26

In the following Examples, coating formulations were prepared as inExample 1 using various inorganic oxides. The coating compositions werecoated onto either acrylic (Cyro-ACRYLITE™, available from Cyro Inc.) orpolycarbonate substrates (Cyro-CYROLON™, available from Cyro Inc.) andcured as previously described. The cured coatings were then subjected tothe Warm Water Adhesion Test. The results are set out below in Tables 13and 14.

TABLE 13 Warm Water Adhesion Test on Acrylic Sample Inorganic oxide 10days @ 57° C. 5 days @ 68° C. 5 days @ 78° C. Cross Hatch test Example17 SiO₂/NaAlO₂ pass pass pass pass 99:1 Example 18 SiO₂/NaAlO₂ pass passpass pass 98:2 Example 19 SiO₂/ZrO₂ pass pass pass pass 95:5 Example 20SiO₂/ZrO₂ pass pass pass pass 90:10 Example 21 SiO₂/SnO₂ pass pass passpass 95:5

TABLE 14 Warm Water Adhesion Test on Polycarbonate Sample Inorganicoxide 10 days @ 57° C. 5 days @ 68° C. 5 days @ 78° C. Cross Hatch testExample 22 SiO₂/NaAlO₂ pass pass pass pass 99:1 Example 23 SiO₂/NaAlO₂pass pass pass pass 98:2 Example 24 SiO₂/ZrO₂ pass pass pass pass 95:5Example 25 SiO₂/ZrO₂ pass pass pass pass 90:10 Example 26 SiO₂/SnO₂ passpass pass pass 95:5

Examples 27 to 30

In the following Examples the effect of the fluorochemical on graffitiresistance was evaluated. Several compositions were coated onto eitheracrylic or polycarbonate substrates and cured as previously described.In the first of two tests the coated substrate was written upon with aSHARPIE™ marker and the ink was allowed to dry. Then removal of the inkwas attempted by rubbing with a paper tissue. If all of the ink wasremoved, the coating was acceptable and rated as “pass”.

In the second test, Rust-Oleum™ spray paint was applied to the coatedsubstrate. The spray can was held about 20 to 25 from the sample and aone-second burst was applied to form a spot of paint. Next the spray canwas held the same distance from the sample and a line of paint wasapplied with a three-second burst. Then the paint was allowed to dry andremoval of the paint was attempted by rubbing with a paper tissue. Ifall of the paint was removed, the coating was rated as a “pass”. Thecoating composition of Comparative Example A was similarly evaluated.

TABLE 15 Coating Sample Composition Substrate Ink Paint Example 27Example 1 Polycarbonate pass pass Example 28 Example 4 Polycarbonatepass pass Comp. E Comp. A Polycarbonate fail fail Example 29 Example 1Acrylic pass pass Example 30 Example 4 Acrylic pass pass Comp. F Comp. AAcrylic fail fail

The above results show that coating compositions of the presentinvention benefit from the incorporation of a fluorochemical and areuseful as anti-graffiti coatings. In contrast, coating lacking thefluorochemical remained soiled by ink and paint.

Example 31

Two white full grain leathers (available from Sadesa, Buenos Aires,Argentina) designated #2040 and #2059 were spray coated with the ceramercomposition of Example 1, using a commercial sprayer and holding theleather sample in a horizontal position. The coating weight was 11grams/meters². The samples were then oven dried for about 10 minutes at70° C. The samples were then cured using a UV chamber with mercury vaporlamps (power setting−300 Joules/seconds/meters²) at a speed of 6meters/minute.

The samples were tested according to the Taber Abrasion Test on Leather.The results are set out below in Table 16.

TABLE 16 Sample Uncoated Coated with Ceramer #2040  75 cycles 225 cycles#2059 125 cycles 600 cycles

Other embodiments of this invention will be apparent to those skilled inthe art upon consideration of this specification or from practice of theinvention disclosed herein. Various omissions, modifications, andchanges to the principles and embodiments described herein may be madeby one skilled in the art without departing from the true scope andspirit of the invention which is indicated by the following claims.

We claim:
 1. A method of making a curable ceramer composition,comprising the step of combining a fluoro/silane component with anadmixture comprising colloidal inorganic oxide and curable binderprecursor, said combining step occurring in the presence of acrosslinkable silane component; wherein the fluoro/silane componentcomprises a hydrolyzable silane moiety and a fluorinated moiety, thecrosslinkable silane component comprises a hydrolyzable silane moietyand a polymerizable moiety other than a silane moiety, and the curablebinder precursor comprises a polymerizable moiety copolymerizable withthe polymerizable moiety of the crosslinkable silane component; saidcombining step further occurring under conditions such that at least aportion of the colloidal inorganic oxide is surface treated by thefluoro/silane component.
 2. The method of claim 1, wherein the admixturecomprises a sol of colloidal inorganic oxides.
 3. The method of claim 2,further comprising the step of stripping the composition to removewater.
 4. The method of claim 3, further comprising the step of addingan organic solvent to the stripped composition to form a coatablecomposition containing from about 5% to about 95% solids by weight. 5.The method of claim 1, wherein the weight ratio of the crosslinkablesilane to the fluoro/silane is between 4:1 and 20:1.
 6. The method ofclaim 1, wherein the crosslinkable silane component is represented bythe formula: (S_(y))_(q)—W^(o)—(R_(c))_(p) wherein S_(y) represents ahydrolyzable silane moiety; R_(c) is a moiety comprising free-radicallypolymerizable functionality; q is at least 1; p is at least 1; and W^(o)is a linking group having a valency of q+p.
 7. The method of claim 1,wherein the fluoro/silane component is represented by the formula:(S_(y))_(r)—W—(R_(f))_(s) wherein S_(y) represents a hydrolyzable silanemoiety; R_(f) represents a fluorinated moiety; r is at least 1; s is atleast 1; and W is a linking group having a valency of r+s.
 8. The methodof claim 1, wherein the curable binder precursor comprises one or more(meth)acrylate or (meth)acrylamide monomers.
 9. The method of claim 1,wherein the inorganic oxide comprises a mixture of a major amount ofsilica and a minor amount of at least one other inorganic oxide.
 10. Themethod of claim 9, wherein the other inorganic oxide comprises alumina.